When manufacturing a product from a plurality of constituents, the properties of these constituents may be critical to the manufactured product. If the properties of the constituents are not within specified boundaries, the product may not meet its specified performance characteristics. For example, in a photographic product, such as an emulsion for coating onto photographic film or paper, if the properties of the constituents (gelatin, dopants, dyes etc) are not within predetermined boundaries, the final product, the photographic emulsion, may not meet its performance characteristics such as speed or grain size.
One known method used to minimise variability in manufacturability due to the effect of raw materials over a fixed time frame involves the isolation of batches of critical constituents. This is commonly referred to as `blocking`. In practice, large quantities of these critical constituents are set aside and used specifically for one particular product. This prevents short term variation in the product performance characteristics.